1. Field of the Invention
The present invention relates to a refrigeration circuit and a method of reducing pressure variations therein. More particularly, the present invention concerns a tuned process tube such that the tube is utilized to attenuate vibrations during operation of a refrigeration circuit.
2. Description of the Prior Art
In a typical vapor compression refrigeration system various components such as a compressor, condenser, evaporator and expansion device are arranged to transfer heat energy between fluid in heat exchange relation with the evaporator and fluid in heat exchange relation with the condenser. Refrigerant lines are used to connect the components such that a closed refrigeration circuit having refrigerant circulating between the components is provided.
Upon initial manufacture of an air conditioning unit, it is necessary to charge the refrigeration circuit by removing water and non-condensable gases from the circuit and replacing same with a refrigerant, as is well known in the art. Many units have a process tube connected to a refrigerant line through which the unit is charged. Upon the charge of refrigerant being transferred to the refrigeration circuit the process tube is sealed such that a permanent joint is made assuring the integrity of the refrigeration circuit. This process tube has then served no other purpose.
In the herein described apparatus and method there is disclosed tuning this process tube by forming a crimp therein at a selected length from the joint with a refrigerant line such that a one-quarter wave length resonator is provided. Consequently, by selecting the appropriate length a vibration attenuation device is provided from a component previously only used for charging the refrigerant circuit upon manufacture. Prior art devices have included forming the lines of a refrigeration system with a plurality of bends such that pressure variations may be absorbed through these bends in the line. Additionally, convoluted flex pipe portions have been provided in a refrigerant line for a similar purpose. Additionally, the use of baffles and other add on or clamp on devices is well known in this art.
In a typical residential or room air conditioning unit a hermetic refrigerant compressor having an electric motor and a positive displacement compressor are sealed within a casing. The pulsating nature of a positive displacement compressor such as caused by pistons reciprocating back and forth creates vibrations. These vibrations may be transmitted either through refrigerant lines directly or through the refrigerant flowing through refrigeration circuit as pressure variations therein. The function of the present device is to attenuate pressure variations within the refrigerant. The vibrations created at the compressor not only serve to provide an additional stress to the components of the system but may also produce noise objectionable to the operator.